The present invention relates generally to surgical instruments, and more specifically to endoscopic instruments for tissue ligation and transection.
In least invasive surgical procedures such as laparoscopy, endoscopy, pelviscopy and thoracoscopy, surgery may be performed within a body cavity without the need to make large incisions to provide access to the body cavity. In laparoscopy, for example, the abdomen is insufflated using a gas such as carbon dioxide. Surgery may then be performed within the abdominal cavity through access ports called trocar sleeves positioned through the abdominal wall. Such trocar sleeves provide a sealed entryway into the abdominal cavity through which long handled instruments may be introduced. To minimize trauma, the trocar sleeves are made of small cross-section, requiring surgical instruments which are also of very small cross-section, typically in the range of 3 to 15 mm in diameter. Such instruments must be elongated so as to reach a surgical site within the abdomen while having substantial rigidity for manipulation from the proximal end of the instrument. Further, laparoscopic instruments must be configured to seal within the trocar sleeve so as to prevent leakage of insufflation gas from the body cavity.
During many surgical procedures, including laparoscopic and other least invasive procedures, it is often necessary to ligate certain tissue structures. Such structures may include arteries, veins, biliary ducts, lymph ducts, uterine ligaments and other vessels and organs. Such structures are frequently continuous, or have no end proximate to the site to be ligated (in contrast to an appendage), and thus preclude the use of closed loop or noose-type ligatures.
Two techniques are currently used for ligating such continuous structures. In one technique, a U-shaped wire clip is positioned with the legs of the clips surrounding the structure, and the legs of the clip are closed tightly onto the structure. Exemplary devices for applying such surgical clips for tissue ligation are described in U.S. Pat. No. 4,616,650, U.S. Pat. No. 5,084,057 and U.S. Pat. No. 4,509,518, which are incorporated herein by reference.
A second technique for ligating continuous structures involves tying a length of suture about the structure either by hand, or using a suture applying instrument such as that described in U.S. Pat. No. 5,129,912, the complete disclosure of which is incorporated herein by reference.
While surgical clip application and suture tying are effective for ligation in certain procedures, such techniques suffer from several drawbacks. Surgical clips are ineffective for ligating larger tissue structures, as the clip legs often have insufficient length and/or spacing to completely surround such structures. For laparoscopic procedures, the small diameter of the trocar sleeves through which instruments are introduced limits the size of the surgical clip appliers and surgical clips which can be used. Surgical clips further suffer from the tendency to slip off the tissue structure after application due to insufficient clamp force of the clip legs.
Suture tying, on the other hand, requires difficult suture manipulation within the restricted surgical workspace and a high level of skill in knot-tying to provide effective ligation. Moreover, the limited size of trocar sleeves as well as the limited visibility afforded the surgeon during laparoscopic procedures greatly complicates the task of tying sutures within the body cavity for purposes of ligation.
While ligation is sometimes performed without tissue transection, ligation is frequently performed for the purpose of sealing off a duct, vessel or other structure to prevent the outflow of blood or other fluid when the structure is transected. When a tissue structure is to be transected, it is often desirable to ligate the structure at two or more locations so as to permit transection between the ligatures.
Devices are known which accomplish both ligation as well as transection of a tissue structure using a single instrument. Such devices are described in U.S. Pat. No. 3,584,628, U.S. Pat. No. 3,545,444, U.S. Pat. No. 3,006,344, U.S. Pat. No. 3,175,556, U.S. Pat. No. 3,735,762, U.S. Pat. No. 4,086,926 and U.S. Pat. No. 3,665,924, the complete disclosures of which are incorporated herein by reference. Generally, such devices apply a surgical clip or, in the case of the devices described in U.S. Pat. No. 3,545,444 or U.S. Pat. No. 3,584,628, a length of wire suture, to each of two locations on the tissue structure separated by a gap. The devices may further include a transecting blade slidable between the ligatures to transect the tissue.
While such ligation/transection devices offer greater convenience than techniques which require separate instruments for ligating and transecting a tissue structure, these devices continue to suffer from the drawbacks of conventional ligating instruments. That is, the clips or wire wraps applied by such devices are of insufficient size for ligating certain tissue structures. Devices suitable for laparoscopic use are particularly limited in size. Moreover, these clips or wraps suffer from the tendency to slip off of the tissue structure after application.
Improved apparatus and methods for ligating and transecting tissue structures are therefore desired which overcome the deficiencies of known devices. The apparatus and method should facilitate ligation at one, two or more sites on a tissue structure. In addition, the apparatus and method should permit ligation and/or transection of tissue structures of various sizes, including the larger vessels and ducts which cannot be ligated using known devices. Desirably, the apparatus and method will facilitate application of a ligature using surgical sutures, without requiring intricate suture manipulation or knot-tying skills. The apparatus and method will preferably allow application of at least two ligatures to a continuous tissue structure, as well as transection of the structure adjacent to or between the ligatures. Moreover, the apparatus and method should be useful in laparoscopic and other least invasive procedures as well as in open surgical procedures.